Electric-current meter



(No Model.)

A. BERNSTEI'N.

ELECTRIC CURRENT METEBNj NO. 269,559. Patented D60. 26, 1882.

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ATTORNEY N P TENS UNITED STATES PATENT QEEICE'.

v ALEX BERNSTEIN, OF BOSTON, MASSACHUSETTS.

ELECTRIC-CURRENT METER.

SPECIFICATION forming part of Letters Patent No. 269,559, dated December26, 1882.

4 Application filed October 4,1882. (No model.)

v To all whom it may concern Be it known that I, ALEX BERNSTEIN, ofBoston, in the county of Sutt'olk and State of Massachusetts, haveinvented certain new and current used in the main line or any branchthereof can be ascertained and conveniently read off at any time in acorrect and reliable manner; and the invention consists of a fulcrumedscale-beam, which carries at one end a traversing and counterbalancedregistering device and at the other end a coil into which is placed asoft-iron core connected by a rod to the register. Below the armcarrying the registering device is suspended a coil, which is surroundedby asecond coil otlargerdiameter, the latter being constantly traversedby the main or branchcurrent, while the smaller coil and the coil on thebeam are traversed at stated periods byan auxiliary current of constantand known strength. The registering device and scale-beam are retainedin a position of rest-to wit, a horizontal position-why means of aspring-catch and fixed rack-bar, which latter is arranged above theregistering device, as will all appear more fully hereinafter andfinally be pointed out in the claims.

In the accompanying drawings, Figure 1 represents a diagram showing theconnection of the different branch circuits with the main circuit andwith the auxiliary circuit, that is used for working all thecurrent-meters at stated intervals of time. Fig. 2 is a side elevationof m yim proved current-meter, partly in section. Fig. 3 is a plan viewof the same,

and Fig. 4 a side view of the registering device drawn on a largerscale.

Similar-letters of reference represent corre sponding parts.-

For the purpose of measuring the current supplied to the main or branchcircuits an auxiliary current is employed, the strength of which isknown and kept constant. This current is thrown through all thecurrent-meters atcertain stated periods of timesay every five minutesendthereby the main current meas-' ured by its action upon the auxiliarycurrent and the measurement mechanically indicated upon thecurrent-meters. Each current-meter is constructed of a verticalstandard, A, which supports an oscillating beam, B, turning onknife-edged trunnions. To one arm of the beam B is applied a traversingregistering device, (J, to which is connected a weight, a, by a wirestring, 1), passingover the pulley b at the outer end of the arm. Theregistering device is also connected by a rod, d, with a soft-iron core,

-I), which is guided in any suitable manner into a coil, D, attached tothe opposite arm of the scale-beam B.

From that arm of the scale-beam which carries the registering device issuspended a coil, E, Whichis inserted or dipped into a coil, E, oflarger diameter, the latter coiltb'eing traversed by the currentof themain circuit. The

interior coil, E, and the coil Dat the outer end of the scale-beam formpart of the auxiliary circuit, through which the current is passed atcertain fixed intervals-of time by a battery and a clock and suitablecircuit-closing devices at the central station. As soon as the auxiliarycurrent isthrown into the line the inside coil, E, will'be drawn downinto the out-side coil, E, and thereby the scale-beam B lowered atthat'side from which the smaller coilissuspendcd.Theauxiliarycurrentpasses at the same time through the fixed coil D atthe opposite end of the scale-beam and causes the iron core to be drawninto the coil, whereby the registering device is moved forward upon thebeam until equilibrium is again established and the beam returned tohorizontal position.

The way or distance which has to be traveled by the registering devicein order to establish equilibrium of the parts is measured by thefollowing formula: Let s be the distance the register has to move; l,thestrength of the main current to be measured; 2', the strength, of theauxiliary current; (J, a constant ot'theinstrumentdependentou thelcngthof wire in both coils and other details. Then 8 is equalto I i G. As itsa current ofconstant and known strength, then s is proportional to I,or, in other words, the distance through which the register moves inorder to establish equilibrium corresponds directly to the strength ofthe current to be measured.

In order to indicate by mechanical means the distance through whichtheregistermoves, a set-screw for holding it in place when adthe arm ofthe scale-beam B which carries the register is made in the shape of arack, and the registering device provided with a small pinion, whichgears with the rack and transmits its motion by a train of gear-wheelsto index-hands moving over dial-plates in the usual manner. The hands ofthe dial can only be moved when the registering device moves in onedirection, they being not moved when the registering device moves in theopposite direction, so that the return motion of the register has noeffect upon the hands, as is well known in registering devices of thisclass. In this way the strength of the main current is indicated bymeans of the auxiliary current every five minutes, or at lougrr orshorter intervals of time, as desired, and thereby the amount of currentpassing over the main line or in any branch thereof to which tne meteris applied accurately determined.

In connection with the registering device of the current-meter, andabove the same, is arranged a fixed horizontal rack-bar, F, which isengaged by means ofa spring-catch, F, applied to the register. As soonas the auxiliary current is made to pass through the coils E and D thebeam is deflected at the left end, and the iron core D will be drawninside of the coil D at the right end. As the register is drawn towardthe right by the action of the coil on the iron core until equilibriumis again established,the beam assumes again a horizon tal position, andno further motion of the register can take place, as the spring catch ofthe same engages the fixed rack-bar. According to the explanation given,the distance which the sliding register was compelled to move'in orderto establish equilibrium of the beam corresponds directly to thestrength of the main current to be measured. After this action has takenplace the auxiliary current is discontinued and the small counter-weighton the left side of the beam brings the sliding register back to itsoriginal position, where it is arrested by the stop (1 on the rod (1coming in contact with the slotted standard f, through which said rodslides. The stop 61 may consist of a collar loose onthe rod, andprovided with justed into the proper position.

The current is furnished in the usual manner by a dynamo-electricmachine and distributed from themain line over the branchlines, in eachof which any number ot'lamps may be placed, as indicated in Fig. 1. Abattery at the central station supplies the auxiliary current for theauxiliary line.

In place of a battery, a small magneto-electric machine may be used. Aclock serves to close the current of this battery every five min utes bymeans of suitable circuit-closing devices, the current beinginterruptedagain after it has acted a certain time-say two or three. minutes. Agalvanometer'and resistance-coils may be used in order to measure andkeep con-.- stant the strength of the auxiliary current.

Having thus described my invention, I claim as new and desire to secureby Letters Patent---' 1. A current-meter composed of a scale beam, of amovable and counterbalanced registering device at one end of the beamand of a fixed coil and a sliding iron core connected to the registeringdevice at the other end oi the beam, of a coil suspended below the endof the beam, carrying the register and placed in an auxiliary circuitwith the coil at the other end of the beam, and of a fixed coil oflarger diameter and surrounding the suspended coil, and being placedinto the main circuit, sub stantially as set forth. .2. The combinationof a scale-beam carry-' ing a movable and counterbalanced registeringdevice upon one arm, a coil and sliding core upon the other arm, a coilsuspended from the arm carrying the register, a fixed coil surroundingthe suspended coil, and a suitable stop mechanism, whereby the registeris stopped when the equilibrium of the parts takes place, substantiallyas and for the purpose set forth.,

In testimony that I claim the foregoing as inyinvention I have signed myname in presonce of two subscribing witnesses.

ALEX BERNSTEIN.

Witnesses:

PAUL GOEPEL, CARL KARP.

